How Can I Sort VARCHAR Fields Numerically in MySQL?
Sorting Varchar Fields Numerically in MySQL: The CAST Function
In certain scenarios, a MySQL varchar field may contain integer values with leading zeros, causing lexicographical sorting to deviate from the desired numerical ordering. To resolve this, the CAST function provides a solution.
Issue:
Consider a table with a field named "number" of type varchar, storing integer values. Despite its data type, "number" contains values like "009" and "042". When sorted using the following query:
SELECT * FROM table ORDER BY number ASC
The result would be:
number 009 042 9
Solution:
To sort by numerical values, MySQL provides the CAST function. By casting the varchar field to a SIGNED INTEGER, the leading zeros are ignored, resulting in correct numerical ordering.
The modified query using the CAST function:
SELECT * FROM table ORDER BY CAST(number AS SIGNED INTEGER) ASC
Will now produce the desired sorting:
number 9 009 042
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